Diagnostic and therapeutic methods based on the L1 adhesion molecule for ovarian and endometrial tumors

ABSTRACT

A method is described for the diagnosis of an ovarian or endometrial tumor or for a prognosis, characterized in that the L1 level is determined in a patient sample, preferably via an anti L1 antibody, the presence of L1 being an indication of the presence of an ovarian or endometrial tumor or a predisposition for such a tumor. Furthermore, methods for treating of ovarian or endometrial tumors are provided.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is filed under the provisions of 35 U.S.C. §371 and claims the priority of International Patent Application No. PCT/EP01/07924 filed 10 Jul. 2001, which in turn claims priority of European Patent Application No. 00 114 788.3 filed 10 Jul. 2000.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for the diagnosis of an ovarian or endometrial tumor or for a prognosis, characterized in that the L1 level is determined in a patient sample, the presence of L1 being an indication of the presence of an ovarian or endometrial tumor or a possible predisposition for such a tumor. This detection is made preferably via a monoclonal anti L1 antibody or a fragment thereof. The invention also relates to pharmaceutical preparations for use in the therapy of an ovarian or endometrial tumor. Furthermore, the present invention concerns a method of treating ovarian or endometrial tumors.

2. Description of Related Art

The diagnosis of specific tumors is based inter alia on the detection of specific tumor antigens (TAG) which may originate from the cytoplasm, the cell surface and the nucleus. In this connection, a distinction is made between tissue, individual and species-specific TAGs which may also be present physiologically as differentiation antigens on cells and between TAGs which are referred to as tumor-specific neoantigens and TAGs as intermediate products of the oncogenesis of a cell type which disappear again with further differentiation. They are detectable as tumor markers by immunochemical methods, above all intracellular antigens (AG) or antigens forming (increasingly) as surface antigens on tumor cells being of interest. Of diagnostic significance are e.g. the oncofetal AG (“OFA”), e.g. the carcinoembryonal AG (in the case of colon carcinoma), the SCC AG (“squamous cell carcinoma antigen”), α1 fetoprotein (in the case of primary liver cell carcinoma), isoferritin and fetal sulfoglycoprotein (in the case of gastric cancer and colon carcinoma), α2⁻H ferroprotein (in the case of a malignant tumor occurring in early childhood), γ⁻ fetoprotein (in the case of sarcomas, leukemias, breast cancers), furthermore “Tennessee AG” (tennagen), “tissue polypeptide AG” (TPA), oncofetal membrane AG (OFMA), tumor-specific transplantation AG (TSTA), membrane-associated tumor AG (MATA) as well as minor antigens such as “A-like” AG, “Forssman” AG, WGL, etc. Another tumor marker used diagnostically so far is CA125 (highly glycosylated cellular mucin which occurs in tumor cells to a greater degree and is released) which marker has been used so far for the diagnosis of human ovarian cancer or endometrial carcinoma, e.g. via the determination of the serum levels or—after operations—via the immunohistological staining of tissue samples with anti CA125 antibodies. However, the diagnosis based on the detection of CA125 has a number of serious drawbacks. For example, increased serum levels of CA125 can also occur in a number of benignant diseases, e.g. in the case of an endometrial inflammation, pelvic inflammation, cirrhosis or also during the menstruation or a pregnancy. Increased CA125 levels are also found in the case of non-gynecologic malignant tumors such as breast cancer, colorectal cancer, pancreatic carcinoma or lung cancer. Thus, this can lead to false-positive diagnoses. CA125 is also found in the case of immunostaining of colon-adenocarcinomas, gastric cancer, lung cancer and atypical hyperplasias of the endometrium. For the early detection of ovarian or endometrial carcinoma the measurement of CA125—in combination with ultrasound—does not yield any satisfactory reliable results either. Thus, with respect to both susceptibility and specificity CA125 is not suited for an early detection of ovarian or endometrial cancer but—if at all—rather for subsequent stages or relapses, however, the above described problems regarding the specificity existing, i.e. the diagnostically hardly acceptable occurrence of false-positive findings.

SUMMARY OF THE INVENTION

Therefore, the invention is based on the technical problem of providing markers which permit an improved and more specific diagnosis of ovarian and endometrial cancers, including the possible distinction between various tumor types and the possibility of detecting metastases and thus improved therapeutic, e.g. surgical, measures. A further technical problem is to provide a therapeutic approach by using L1 as therapeutic target. The solution to this technical problem is achieved by providing the embodiments characterized in the claims.

It has surprisingly been found that the L1 adhesion molecule represents a highly specific marker in body fluids (e.g. in the blood serum, ascites and fluid from Douglas coule de sac) and tissue from ovarian and endometrial tumors, above all for highly aggressive forms of these tumors. L1 is a neuronal adhesion molecule of 200-230 kDa, which as regards its structure belongs to the Ig superfamily. L1 is a protein associated with cell migration, which in the brain is involved in the neuronal migration in the cerebellum and in the fasciculation of neurites. L1 has several binding partners among them L1 itself, the proteoglycan neurocan and various integrins (Kadmon et al., Differentiation 61: 143-150, 1997). Soluble L1 can stimulate the migration of tumor cells and hence promote metastasis (Mechtersheimer et al., JBC 2001, in press). In the screening experiments resulting in the present invention it turned out that L1 is not expressed in normal tissues with the exception of peripheral nerves and ganglions. In benignant ovarian and endometrial tumors no L1 expression could be detected, and the screening of other malignant tumors (breast, prostate, cervix) was also negative. It showed that L1 is expressed on highly aggressive serous papilloma carcinomas of the ovary and the endometrium. Soluble L1 was detectable in the serum and ascitic or pleural fluids of tumor patients but not in normal sera and body fluids or in patients having benignant tumors. Preoperative samples which were obtained by gynecologic curettage were positive in serous papilloma carcinomas of the endometrium and with the involvement of the ovary. Thus, the expression of L1 as cell surface molecule in the serum and in body fluids is highly significant as regards the early detection of aggressive ovarian and endometrial tumors and also as regards the prognostication. Therefore, the L1 detection permits the early detection and accurate diagnosis or prognosis of aggressive ovarian and endometrial tumors. Thus, the subject matter of the present invention relates to a method for the diagnosis of an ovarian or endometrial tumor or for a prognosis, characterized in that the L1 level is determined in a patient sample, the presence of L1 being an indication of the presence of an ovarian or endometrial tumor or a predisposition for such a tumor.

Suitable methods of obtaining a patient sample are known to a person skilled in the art. The L1 adhesion molecule is detected via common methods, through utilizing the amino acid sequence of the L1 protein (SEQ ID NO: 15) or the nucleic acid sequence of the corresponding gene (SEQ ID NO: 14). (Reid, R. A. et al., J. Mol. Neurosci. 3:127-135, 1992, hereinafter “Reid et al.”; Ebeling et al., Eur J Immunol. 26:2508-2516, 1996, hereinafter “Ebeling et al.”) In this connection, the detection may refer to the transcription (detection of the concentration of the mRNA via common methods) or the L1 protein per se, the latter being preferred. The expression “the presence of L1 an indication of the presence of an ovarian or endometrial tumor or a predisposition for such a tumor” also comprises the situation in which the concentration of L1 is increased as compared to a control (e.g. body fluid or tissue of a healthy person).

Reid et al. characterizes L1 in humans using cDNA structural and mRNA expression analyses to present the entire coding sequence for human L1, predicting a 1253-amino acid protein (SEQ ID NO: 16). Reid et al. describes two forms of L1, which differ by the presence or absence of a 12-bp cytoplasmic segment (SEQ ID NO: 17 and SEQ ID NO: 18), that are expressed in both the human and mouse. Additionally, Reid et al. describes that the segment is encoded by a single exon that can be alternatively spliced to give rise to the two forms, which appear to be expressed in tissue-specific patterns. (Reid et al., Abstract, pg. 127.)

In a first preferred embodiment of the method according to the invention the L1 level is determined by determining L1 as cell surface molecule in tissue. Suitable tissues are removed tumor tissue and cell material obtained by curettage, the tissue obtained from a gynecologic curettage being preferred.

In a second preferred embodiment of the method according to the invention the L1 level is determined by determining L1 in soluble form in a body fluid. Suitable body fluids are blood serum, ascitic or pleural fluid or fluid from Douglas coule de sac, serum being preferred.

A third preferred embodiment does not carry out the detection of L1 but the detection of L1-specific antibodies by means of (recombinant) L1. For this purpose, purified (recombinant) L1 is immobilized on the surface of microtitration plates and then incubated with patient serum. Bound antibodies are then detected by means of an enzyme-conjugated second antibody and a color reaction.

In a fourth preferred embodiment L1 mRNA is detected in a body fluid sample, preferably in blood serum.

Suitable detection methods of L1, L1 mRNA and L1 antibodies, respectively, and suitable specific probes are known to the person skilled in the art, the detection of L1 protein via specific antibodies being preferred, the same or different antibodies being usable for both the soluble form and for the form on the cell surface.

In the particularly preferred first and second embodiments of the method according to the invention the L1 level is therefore determined by contacting the patient sample with an anti-L1 antibody or a fragment thereof and then determining whether the anti-L1 antibody or the fragment thereof has been bound to L1. In this regard reference is made to FIG. 6A-C.

The antibodies suitable for this purpose may be monoclonal, polyclonal or synthetic antibodies or fragments thereof. In this connection, the expression “fragment” refers to all parts of the monoclonal antibody (e.g. Fab-, Fv- or “single chain Fv” fragments) which have the same epitope specificity as the complete antibody. The production of such fragments is known to the person skilled in the art. The antibodies according to the invention are preferably monoclonal antibodies. The antibodies according to the invention can be prepared according to standard methods, L1 or a synthetic fragment thereof, which is present in both L1 forms (soluble/anchored on the cell surface) preferably serving as an immunogen. This polypeptide or peptide and the fragment thereof, respectively, can be produced e.g. by obtaining the corresponding gene, cloning and recombinant expression. Methods of obtaining monoclonal antibodies are known to the person skilled in the art. Anti-L1 antibodies suitable for the diagnostic method according to the invention are commercially available. These are e.g. the primary human monoclonal anti L1 antibodies 15551A (Company of Pharmingen, San Diego, USA) or MCA1753 (BIOZOL Diagnostica Vertrieb GmbH, Eching, Germany).

In an even more preferred embodiment of the method according to the invention the L1 level is determined via a primary monoclonal anti-L1 antibody and a commercially available secondary antibody. The secondary antibody may carry any label which may be detected. It is, however, preferred that this secondary antibody may be biotin-conjugated and may be detected by using streptavidin peroxidase. The person skilled in the art is perfectly familiar with methods of carrying out this embodiment. The detection of L1 (e.g. via ELISA) can also achieved with only one (monoclonal) antibody since L1 in serum is multimeric (c.f. Example 3, FIG. 5B).

In a preferred embodiment the patient sample is immobilized, e.g. as paraffin section. The patient sample can also be absorbed to the wall of a plastic dish by common methods such that L1 does not loose its bonding specificity e.g. for a specific antibody added thereto.

In a preferred alternative embodiment of the method according to the invention the anti L1 antibody or the fragment thereof is immobilized, i.e. it is absorbed e.g. to the wall of a plastic dish without loosing its bonding specificity for L1. Then a patient sample is added.

The bonding of the antibody can be detected by common methods, e.g. Western blot, ELISA, radioimmunoassay (RIA), etc., RIA and ELISA being preferred.

The above mentioned preferred fourth embodiment of the method of the present invention is based on the detection of L1 mRNA by RT-PCR. Ebeling et al., Eur. J. Immunol. 26:2508-2516, 1996, hereinafter “Ebeling,” has shown that different isoforms of human L1 (i.e. hemoatopoietic L1 vs. neural L1) can be distinguished on the basis of L1 exon 27 usage. Using primers deduced from the human L1 cDNA sequence (EMBL/GenBank Accession Number M74387) (see Ebeling et al., page 2509), Ebeling cloned a full length L1 transcript from immortalized myeloma cancer cells. DNA sequence analysis of a L1-specific cDNA clone from these cells showed nearly complete identity to the published DNA sequence derived from neuroblastoma cells except for one difference. Ebeling found that the cDNA clone showed a deletion of five amino acids close to the N-terminus of the L1 protein, which is encoded by exon 2 of the human L1 gene, and deposited this cDNA sequence at EMBL/GenBank Accession Number Z29373. Also, the cytoplasmic exon encoding the amino acids RSLE (exon 27) that was previously shown in the neuronal L1 form of human embryonic brain was not present in the myeloma L1 cDNA clone. Ebeling carried out RT-PCR on sorted cell populations and on additional lymphocyte and monocyte human tumor cell lines to analyze the use of exon 27 in lymphocytes and monocytes. Ebeling designed primers to distinguish between the absence or presence of exon 27 according to the size of the amplified PCR fragment. Ebeling discovered that the hemapoetic cells analyzed did not express exon 27. (Ebeling et al, pg. 2513, paragraph 2-4. As shown by Ebeling, exon 27 encodes 4 amino acids in the cytoplasmic tail of L1. By utilizing RT-PCR and specific primers (SEQ ID NO: 8, 9, 10, 11, and 12) for this region of L1, it has now been discovered that ovarian tumors (established cell lines and tumor specimens express the neural form of L1 which is characterized by an insertion of 12 nucleotides (FIG. 4). Using the same primers (SEQ ID NO: 8, 9, 10, 11, and 12) it is observed that L1 specific mRNA is detected in tumor patient sera. RT-PCR detection of tumor derived mRNA (possibly derived from tumor cells in the blood) in addition to protein detection by ELISA are demonstrated as sensitive techniques for diagnosis.

Based on the present invention a kit was also developed which is of use for the diagnostic method according to the invention and preferably contains an anti L1 antibody or a fragment thereof and in addition L1 or a bond-active part thereof for the purpose of control. The expression “bond-active part” refers to a fragment which reacts with the antibody with which the whole molecule reacts as well. Depending on the development of the kit, the antibody can be conjugated to another unit, e.g. a marker, and/or it can be immobilized on a solid carrier (substrate). The kit can also contain a second antibody for the detection of L1/antibody complexes. The antibody or the fragment thereof may be present in free form or be immobilized on a solid carrier, e.g. a plastic dish, a test tube, a microtitration plate, a test rod, etc. The kit may also contain instructions which describe the use of the antibody or a fragment thereof in an assay for the detection of a predisposition or the presence of a tumor. The kit can also contain suitable reagents for the detection of labelings or for the labeling of positive and negative controls, wash solutions, dilution buffers, etc.

In the case of a positive diagnostic detection of an ovarian or endometrial tumor by means of the above described anti-L1 antibodies or fragments thereof, immunotherapy via the sensibilization of tumor-specific T lymphocytes can also be carried out according to known methods with the above mentioned antibodies or fragments thereof or with peptides which are derived from L1 (on the basis of the known amino acid sequence) and have preferably a length of at least 9-12 amino acids. In addition, antibodies against L1 can also be used with the intention to use L1 as a tumor-specific target antigen.

Thus, the present invention also relates to a pharmaceutical preparation which contains an anti L1 antibody or a fragment thereof, or a peptide derived from L1, or a L1 antisense oligonucleotide.

The antibodies are preferably monoclonal antibodies. In a particularly preferred embodiment said monoclonal antibody is an antibody originating from an animal (e.g. mouse), a humanized antibody or a chimeric antibody or a fragment thereof. Chimeric antibodies resembling human antibodies or humanized antibodies have a reduced potential antigenicity, however, their affinity for the target is not lowered. The production of chimeric and humanized antibodies and of antibodies resembling human antibodies, respectively, was described in detail (see e.g. Queen et al., Proc. Natl. Acad. Sci. USA 86 (1989), 10029, and Verhoeyan et al., Science 239 (1988), 1534). Humanized immunoglobulins have variable framework regions which originate substantially from human immunoglobulin (with the designation of acceptor immunoglobulin) and the complementarity of the determining regions which originate substantially from a non-human immunoglobulin (e.g. of a mouse) (with the designation of donor immunoglobulin). The constant region(s) originate(s), if present, also substantially from a human immunoglobulin. When administered to human patients, humanized (and the human) antibodies offer a number of advantages over antibodies of mice or other species: (a) the human immune system should not regard the framework or the constant region of the humanized antibody as foreign and therefore the antibody response against such an injected antibody should be less than against a completely foreign mouse antibody or a partially foreign chimeric antibody; (b) since the effector region of the humanized antibody is human, it interacts better with other parts of the human immune system, and (c) injected humanized antibodies have a half life which is substantially equivalent to that of naturally occurring human antibodies, which permits to administer smaller and less frequent doses as compared to antibodies of other species.

In a preferred embodiment thereof, L1 mAb is labeled with (123)I for imaging and injected i.p. or i.v. as described (vanZanten-Przybysz, I. Int. J .Cancer 92:106-114, 2001). MAb to L1 is injected after stable conjugation with cytotoxic drugs in order to kill tumor cells. Examples of such cytotoxic compounds are radionuclides, toxic proteins (e.g. saporin), chemotherapeutic agents or further antibodies with other specificity (e.g. against T cells, e.g. CD3), so that bifunctional antibodies form which effect the killing of tumor cells by means of cytotoxic T cells.

In another preferred embodiment, overexpression of L1 in ovarian and endometrium tumors can be used to prime cytotoxic T lymphocytes in order to kill tumor cells in situ.

-   -   A) Peptides derived from the sequence L1 may be used to         vaccinate tumor patients. Preferably, a mixture of L1-peptides         restricted by HLA-A1 (ATEGWFIGF (SEQ ID NO: 1) and GSDDSLADY         (SEQ ID NO: 2)), HLA-A2 (LLANAYIYV (SEQ ID NO: 3) and WLDEDGTTV         (SEQ ID NO: 4)) and HLA-A3 (VLTGYVLSY (SEQ ID NO: 5)) in an         emulsion with GM-CSF and Montanide ISA-51 adjuvant(Seppic,         Fairfield ,NJ, U.S.A.) are used. Patients receive a vaccine         comprising the 5 L1 peptides (50-200 μg, preferably 100 μg each)         and 150-200 μg (preferably 190 μg) of the HLA-DR-restricted         tetanus helper peptide AQYIKANSKFIGITEL (SEQ ID NO: 6). This         peptide represents peptide p2 of tetanus toxoid (residues         830-844) plus an amino-terminal alanine residue to prevent         formation of pyroglutamate from the N-terminal glutamine         residue. Tetanus peptide p2 is a promiscuous binder to HLA-DR         molecules. Vaccines are administered with 150-250 μg (preferably         225 μg) GM-CSF in Montanide ISA-51 adjuvant. Each patient is         preferably immunized at days 0, 7, 14, 28, 35 and 42 for a total         of 6 immunizations as described by Yamshchikov et al Int. J.         Cancer 92:703 (2001). The individual time frame, doses and         number of immunizations can be determined by a medical doctor         depending on the kind of tumor, tumor growth, presence/absence         of metastasis and patient's data (weight, age etc.).     -   B) Dendritic cells derived from tumor patients may be pulsed         with the above mentioned L1 peptides as described by Lau et         al J. Immunother 24:66-78 (2001). The dendritic cells are         preferably obtained by incubation of plastic-adherent peripheral         blood mononuclear cells from tumor patients with IL-4 and GM-CSF         for 8 days in serumless medium. The dendritic cells are then         pulsed with L1 peptides (each at approximately 50 μg/ml) for         overnight and then used for (intravenous) infusions.

In a further preferred embodiment, the overexpression of L1 in ovarial or endometrial tumors is treated with L1 antisense oligonucleotides. Since cell migration is a prerequisite of tumor cell dissemination it is advisable to eliminate L1 from the tumor cells. This can be achieved by established antisense technology. An L1 antisense oligonucleotide is used to downregulate L1 expression in tumor cells. It corresponds preferably to the sequence AGGCTGTCGTCACTGCCCA (SEO ID NO: 7) and is the inverse complement of nucleotides +3593/3611 of the sequence of human L1. The phosphorothioate oligo-nucleotide is preferably injected into the peritoneum of the tumor patient at doses between 1-12 mg/kg to achieve significant concentrations of oligonucleotide. The individual time frame, doses and total number of administrations can be determined by a medical doctor depending on the kind of tumor, tumor growth, presence/absence of metastasis and patient's data (weight, age etc.).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A: Endometroid ovarian adenocarcinoma composed of tubular glands and lined by non-mucin secreting stratified epithelium. Immunohistochemical staining with anti L1 antibody shows strong heterogenous membral staining.

-   -   B: Serous carcinoma of the ovary showing papillary and slit like         configurations with solid tumor masses in the stroma. Strong         positive immunohistochemical staining with anti L1.     -   C: Omentum with disseminated tumoral glands and desmoplastic         reaction. Strong homogeneous immunostaining of tumoral cells by         anti L1 antibody.     -   D: Appendical wall infiltrated by ovarian carcinoma cells.         Strong homogeneous staining of tumoral cells by anti L1         antibody. No staining of normal mucosal glands and lymphatic         tissue. Small peripheral nerve bundles show strong positive         staining.     -   E: Vaginal wall showing small tumoral mass in the lamina propria         and small tumor emboli in the dilated lmyphatics. Immunostaining         with anti L1 shows strong homogeneous staining.     -   F: Ovarian carcinoma embolus in the lymphatics of the myometrium         showing hetergeneous membranous staining of tumoral cell by anti         L1.

FIG. 2: Detection of L1 from curettage material

-   -   A: Tissue obtained from curettage     -   B: Control sections from ovarian adenocarcinoma

FIG. 3: Detection of soluble L1 in body fluids (1F-14F) and sera (1S-32S) by means of ELISA. The samples 4F, 5F, 8F, 12F and 23F originate from female ovarian cancer patients.

FIG. 4: 1%-Agarose gel after PCR analysis of exon 27 usage

-   -   mRNAs from ovarian tumor speciments or known tumor cell lines         (AR, OAW, Mel63) were isolated and transcribed in cDNA. These         cDNAs were used as template for PCR analysis of exon 27 usage,         Plasmids encoding both forms were used as control (−RSLE/+RLSE).

FIG. 5: Comparison of two different ELISA formats

-   -   A.: Microtiter plates were coated with L1 mAB 1 followed by         blocking with 3% BSA/TBS and incubation with patient sera as         described in Example 2. Bound soluble L1 was detected using         biotinylated L1 mAB followed by Streptavidin-Peroxidase. This         ELISA format can detect dimeric (multimeric) and monomeric L1.     -   B. The ELISA was carried out as described in A but bound soluble         L1 was detected using L1 mAB 1 followed by         Streptavidin-Peroxidase. This ELISA format can detect only         dimeric (multimeric) L1.

FIG. 6: A: Ovarian tumor specimens were lysed and analysed by SDS-PAGE and Western blotting using an antibody to the cytoplasmic portion of L1

-   -   B: Sera from tumor patients were immunoprecipitated with L1         antibody coupled to sepharose, separated by SDS-PAGE and         analysed by Western blotting using the same anti L1 antibody     -   C: Sera of tumor patients and normal individuals were analysed         by ELISA for the presence of soluble L1. The number of patients         from each groups is indicated in brackets.

The following examples explain the invention.

EXAMPLE 1

The Examination of Curettage Tissue Shows a High Correlation between the Expression of L1 and the Clinical Stage and the Pathological Degree of the Tumors, Respectively

Tumor tissue is embedded in paraffin according to standard methods and serial sections are made. Following the treatment of the sections in the microwave oven (10 min., 92° C.) in the presence of 1 mmol EDTA (pH 8.0) immunostaining of the tissue is carried out by means of the MCA1753 antibody (Biozol Diagnostica Vertiebs GmbH). The bound first antibody is detected by means of an enzyme-coupled second antibody (Vector ABC Kit; www.vectorlabs.com). Some exemplary stainings are shown in FIG. 1. The clinical data are listed in Tables 1 and 2.

FIG. 2 shows that L1 can also be detected by means of curettage tissue. Using the above described procedure, a similar staining pattern as on the tumor sections results. The determination of L1 by means of curettage material permits an early preoperative classification of the tumor within the meaning of Tables 1 and 2.

EXAMPLE 2

ELISA Shows the Presence of Soluble L1 in sera and Ascitic Fluid of Tumor Patients, a Correlation between the Presence of L1 and the Tumor Type (Ovarian and Endometrial Tumor) being Observed.

Samples of body fluids (ascites, serum) were tested for the presence of soluble L1 using a “capture” ELISA. For this purpose, microtitration plates were coated with the human anti L1 antibody (concentration: 1 μg/ml) described in Example 1 and then a blocking step was carried out with 3% BSA in PBS (45 min., room temperature) to eliminate the non-specific bonding to the plate. The body fluid was added at differing concentrations (1:2 and 1:10 of the fluid in 3% BSA in PBS), and incubation was carried out at room temperature for 1 hour. Therefore, four wash steps followed in Tris-buffered common salt solution (TBS, pH 8.0, in the presence of 0.02% Tween-20). Bound soluble L1 was determined by the addition of human biotin-conjugated anti L1 antibody. For this purpose, the biotinylated antibody MCA1753 is added to the microtitration plates for 1 hour. This was followed by 4 wash steps as described above. Another incubation at room temperature for 1 hour with peroxidase-conjugated streptavidin (Dianova Hamburg, Germany) follows. Finally, another 4 wash steps are carried out. Hereinafter the substrate solution is added to the microtitration plates and upon appearance of the color reaction the result is evaluated on the ELISA reader. The results are shown in FIG. 3.

EXAMPLE 3

A New ELISA Format for the Detection of Soluble L1

The ELISA described above in Example 2 used the coating of the microtiter plate with L1 mAb 1 (capturing monoclonal antibody) and the detection of soluble L1 with a biotinylated (or otherwise labelled) L1 mAb 2 (detecting monoclonal antibody). This type of ELISA is termed G/K format. We have now developed another format in which we use both for capturing and detection the same mAb to L1 (K/K format). In FIG. 5A and B a comparison of both types of ELISA is shown using a positive serum (CA526, ovarian tumor patient) and seval control sera from unrelated tumors. It is obvious that the new ELISA format in FIG. 5B gives a better signal to noise ratio (appr. 5-8 fold) than the previous format shown in FIG. 5A. As the K/K format can only work when the antibody epitope for detection is not blocked by the antibdy used for capturing, these results implicate that in the serum sample the soluble L1 is dimeric or multimeric. The control data performed in FIG. 5 with both types of ELISA using monomeric and dimeric L1 (the L1-Fc fusion protein is dimeric) support this notion.

EXAMPLE 4

PCR Analysis for Detecting L1 mRNA in Tumor Samples

Primer sequences for PCR analysis are deduced from the chimeral human L1 cDNA sequence (EMBL/GenBank accession number M 74387; SEQ ID NO: 16). For the detection of human mRNA encoding L1 in tumor tissue or patient serum samples mRNA is isolated using commercial kits (Roche Molecular Biochemicals) and transcribed into cDNA. A nested PCR approach is used with the following primer combinations: First amplification primer 1: ACTGAGGGCTGGTTCATC (SEQ ID NO: 8)(sense), primer 2: CTTGCACTGTACTGGCCA (SEQ ID NO: 9)(antisense)(one cycle 45 sec, 94° C., 30 cycles of 1 min at 94° C., 1 min at 56° C., 1 min at 72° C.). For the second PCR 1 μl of the first PCR reaction is used with primer 1: ACTCAGTGAAGGATAAGGAG (SEQ ID NO: 10)(sense), primer 2: TTGAGCGATGGCTGCTGCT (SEQ ID NO: 11)(antisense). In an alternative protocol the following primers are used: primer 1: AGGTCCCTGGAGAGTG (SEQ ID NO: 12) (sense); primer 2: TTGAGCGATGGCTGCTGCT (SEQ ID NO: 11) (antisense). The temperature profile for the PCR reaction are as described above. PCR products are preferably separated on a 2% agarose gel containing 0.5 μg/ml ethidium bromide. As an alternative, the gel is blotted and hybridized with the labeled L1 oligonucleotide probe (TCTGAGGCCCGACCGATGAAAGATGAGACCTTC (SEQ ID NO: 13)) by southern blotting to increase the sensitivity.

TABLE 1 Ovarian carcinomas Seeding to Seeding Distant Follow Case Histological Histological serosal to Metastase Clinical up L1 No type grade surface omentum S stage (month) Reccurance Outcome staining 1 Serous moderate-poorly + + − IIIc 9 AWD + 2 poorly + + Lung IIIc/IV 1 DOD + Breast 3 ″ moderate-poorly + + Brain IV 24 + DOD + 4 ″ moderate-poorly − + − IIIc 36 + DOD + 5 ″ poorly + + − IIIc 26 + DOD + 6 ″ moderate-poorly − + − IIIc/IV 35 + DOD + 7 ″ moderate-poorly + + − IIIc 22 + DOD + 8 ″ well + − − Ic 22 − NED − 10 ″ poorly − + − IIIc 62 + DOD + 11 ″ poorly + + Lung Liver IIIc/IV 18 + DOD + 13 ″ poorly − − − Ic 77 − NED − 14 ″ poorly + − Liver IIIc 5 − AWD + 15 ″ poorly + − − IIIc 11 − AWD + 16 ″ moderate + − III No information + 24 ″ moderate + − Lung IV 21 + AWD + 17 Endometroid moderate − − − Ic 20 − NED − 18 ″ poorly − − − Ic 54 − NED − 19 ″ poorly − − − Ic 55 − NED − 20 ″ moderate − − − Ic 26 − NED − 21 ″ moderate − − − Ia 45 − NED − 22 ″ poorly − − − Ib 38 − NED − 23 ″ moderate − + − IIIc 6 − AWD + 25 ″ moderate + + − IIIc No information + 26 ″ poorly + − Liver IIIc 35 − DOD + 27 ″ moderate − − Vagina IIIc 12 + DOD + 28 ″ poorly + + Lung IV 20 − AWD + 29 ″ poorly + + − IIIc 17 + DOD + 30 ″ poorly + + Lung IV 6 + AWD + 31 ″ moderate-poorly + + − IIIc No information + 32 ″ moderate + + Ic 35 − NED + AWD: alive with disease DOD: died of disease NED: no evidence of disease

TABLE 2 Uterine carcinomas Seeding to serosal surface Follow Case Histological Histological and Adnexal Clinical up L1 staining No type grade omentum involvement stage (month) Recurrance Outcome curretage endometrium ovary *1 Endometroid poorly + + IIc ? + DOD ND + + 2 ″ moderate + + IV 21 + DOD ND + + 3 Serous poorly + + IIIc No information + + + 4 ″ poorly + + III ″ + + + 5 ″ moderate + + * ″ ND + + 6 ″ poorly + + * ″ + + + 7 ″ poorly + + IV 10 + DOD ND + + 8 ″ poorly + + IV  5 + DOD + + + 9 ″ poorly + + IIIc 26 + DOD ND + + 10 ″ moderate-poorly + + IIIc 22 + DOD ND + + 11 ″ poorly − − Ib  6 − NED − − − 12 ″ moderate poorly − − Ic 28 − NED − − − *Only two cases of endometroid-type uterine carcinomas with advanced stage with the involvement of the adnexa and are shown in Table 2. These tumors were positive for L1 in the endometrium and the ovary and the patients had a bad prognosis. Additionally, 38 patients with endometroid-type tumors were studied all of which were in low clinal stage, were negative for L1 and had a good prognosis (follow-up between 8-54 months). 

1. A method for the diagnosis of an ovarian or endometrial tumor, said method comprising determining the L1 level in a patient sample, wherein the L1 is an adhesion protein of SEO ID NO: 15, or an isoform thereof, the presence of L1 being an indication of the presence of an ovarian or endometrial tumor.
 2. The method according to claim 1,wherein the L1 level is determined by determining L1 as a cell surface molecule in tissue.
 3. The method according to claim 1, wherein the L1 level is determined by detecting L1 in soluble form in a body fluid.
 4. The method according to claim 3, wherein the body fluid comprises serum.
 5. The method according to claim 1, wherein the L1 level is determined by contacting the patient sample with an anti L1 antibody or an antigen binding fragment thereof and then determining whether the anti L1 antibody or the fragment thereof has been bound to L1.
 6. The method according to claim 5, which is carried out as a radioimmunoassay or ELISA.
 7. The method according to claim 1, wherein the L1 level is determined by determining the presence of anti L1 antibodies or an antigen binding fragment thereof in the patient sample by means of binding to L1.
 8. The method according to claim 1, wherein the L1 level is determined by determining the presence of L1 mRNA in a body fluid.
 9. The method of claims 8, wherein said determining step comprises RT-PCR.
 10. The method according to claim 3, wherein the body fluid comprises a fluid selected from the group consisting of blood serum, ascites, pleural fluid, and Douglas coule de sac fluid.
 11. A method of screening a patient for ovarian and/or endometrial carcinoma, comprising determining whether L1 is present in the patient that is non-attributable to expression of L1 in peripheral nerves and ganglions of the patient, and wherein the L1 is an adhesion protein of SEQ ID NO: 15, or an isoform thereof.
 12. The method according to claim 11, wherein said carcinoma comprises a serous papilloma carcinoma, and said determining step comprises analyzing a fluid from the patient, wherein said fluid is selected from the group consisting of serum, Douglas coule de sac, ascitic and pleural fluids.
 13. The method according to claim 11, wherein said determining step comprises analyzing an ovarian tissue sample of the patient.
 14. The method of claim 1, wherein the isoform of L1 is selected from hematopoietic L1 and neural L1.
 15. The method of claim 14, wherein the soluble from of hematopoietic L1 or neural L1 is detected in a body fluid.
 16. A method for the diagnosis of an ovarian or endometrial tumor, said method comprising the use of a specific anti L1 antibody or an antigen binding fragment thereof that binds to the L1 protein, wherein the L1 protein is an adhesion protein of SEQ ID NO: 15 or an isoform thereof.
 17. The method of claim 16, wherein said method comprises the use of said antibody for the detection of soluble forms of hematopoietic L1 or neural L1 in a body fluid. 